(a) Technical Field
The present disclosure relates to a method of manufacturing a semiconductor device which includes silicon carbide (SiC).
(b) Description of the Related Art
In accordance with trends towards large size and large capacity of an appliance in recent years, it has become necessity for a power semiconductor device to have a high breakdown voltage, a high current, and a high speed switching characteristic.
Accordingly, studies and development on a metal oxide semiconductor field effect transistor (MOSFET) which uses silicon carbide (SiC), instead of a MOSFET using silicon of the related art, are increased. Particularly, development on a vertical trench MOSFET is increased.
In the case of a vertical trench MOSFET, an etching technology which forms a trench to be suitable for a semiconductor substrate is required. Further, silicon carbide is a material having a strong covalent bond, so that a hardness of silicon carbide is higher than that of silicon and an oxidation resistance is stronger than that of silicon. Therefore, a mask which has a higher hardness than silicon carbide is required at the time of etching process in order to overcome etch difficulty.
Therefore, when a trench is formed in a silicon carbide substrate, a metal mask which has a hardness higher than silicon carbide is used. In this case, the metal mask is formed by a lift-off process. However, when the trench is formed using such a metal mask, metal residuals may remain in the trench.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure, and therefore it may contain information that does not form the related art that is already known in this country to a person of ordinary skill in the art.